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Discussion Starter · #1 · (Edited)
I'm curious if the alternator can provide enough power to run without the battery. I am guessing it would not work because the electronics probably expect a battery at all times.

In a previous vehicle (2001) I had a battery fail while driving and I was able to keep going for a while (like 15-30 minutes) before the vehicle stalled.

In a similar vein, if you had a shorted out battery could you jump start your car? I have dealt with shorted out batteries in the past, both with my vehicle and others, and even with jumper cables have never been able to start the car if the battery is toast. I'm looking for a battery power bank/jump starter that could jump start a car in this case. I see NOCO makes some heavy duty ones now that go past 6000 amps. I see youtube videos where people start and run their diesel trucks with just a battery bank (no battery connected) so at least on some vehicles it is possible. Not sure about cherokee.
 

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6000amps for .00001seconds isnt adequate since you have to crank for several seconds.. all the marketing wank is pretty good sounding but is mostly fictional.
I have a 1000amp peak jump box and it wouldnt jump a v8 with a weak battery. I'd expect its good for 100-200 amps for several seconds at most.

You need the battery or you could risk damaging much more expensive parts in the car.
if your battery is in dubious condition replace asap is the best advice I have to offer you.

That being said a jump box protects you from a battery that drops a cell and you need to limp it home or to the parts store.
as well as a weak battery that doesnt have enough ooompf due to super cold weather/age etc.. or leaving lights on

Cold lithium jump boxes are terrible unless they have a preheat function they are affected MUCH more by cold vs lead acid... ie they work better if you have them in warm house vs stored in car in cold parking lot.
 

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Why don't you try it and tell us how it works.....no it will not work.
A failing or failed battery will work for a while as long as the alternator is working, but in the absence of a battery at all it will not run if there is the slightest hiccup in electrical power to the PCM
 

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Discussion Starter · #4 ·
Why don't you try it and tell us how it works.....no it will not work.
A failing or failed battery will work for a while as long as the alternator is working, but in the absence of a battery at all it will not run if there is the slightest hiccup in electrical power to the PCM
I was hoping someone else would try it for me
 
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Discussion Starter · #5 ·
I have done more research and as per my second question, yes there are jump boxes that will do the job even without a battery. Unfortunately all the brands like to "fake" their numbers so finding real data is tough. It seems some of the best out there these days can do around 600CCA which is good enough to start with a totally failed battery.
 

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I bought one of these pocket jump starters about 3 years, but a slightly cheaper version. Out of curiosity I disconnected the battery on my 4.0 XJ to see how times I could start it....got bored at the 8th start :)

Wouldn't do it on the KL unless in emergency, what with all the complicated electronics.
 

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The pocket jump starters are not to be connected to the battery after the vehicle is started. They all state this in the operating manual. They will be damaged if not removed relatively soon after being started
 

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Discussion Starter · #8 ·
The pocket jump starters are not to be connected to the battery after the vehicle is started. They all state this in the operating manual. They will be damaged if not removed relatively soon after being started
With some of the newer ones this is no longer true.
 

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For most people who cannot perform their own proxy alignment, it will most likely cost much more than an uber ride to get a new battery. People have already had blimps in power and needed a proxy alignment with a weak battery still in, so I could only image if it were missing a battery completely.
 
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First, to clear up a couple misconceptions: The car will absolutely have enough juice to run on the alternator alone. This is how cars operate. If they didn’t, the battery wouldn’t charge while you were driving, and it would eventually go dead. The battery is mostly there just to start the vehicle. That being said, the extensive electronics in today’s vehicles probably wouldn’t like being without the battery, as it also acts as a buffer in case of voltage sag. Case in point: all the electrical issues that pop up on our Jeeps when the battery starts to go bad. Second, if your car’s battery back in 2001 died while you were driving, your car wouldn’t stall out after a while, as you claim happened. Older cars, once running, can continue running indefinitely with the battery removed. If something electrical died in your car the way you describe, it was likely the alternator. Or you broke the alternator/serpentine belt. If the alternator dies, the engine will continue running on battery power until the battery finally runs out of juice.
 

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I'm wondering what the Intelligent Battery Sensor has to say about all of this. Since it would be detecting zero current if there were no battery, I would think all kinds of weird things would be happening. There are plenty of posts on this forum about the IBS going bad and causing many issues. Don't think I saw any about the car not running though. Didn't look hard enough?

Sudden electrical surges may kill the engine if you are running without the battery. Even early cars will die if you are running at idle (low current being generated by the alternator) and you turn on the lights (sudden surge). I've witnessed that myself.

Running without a battery is a bit different than running with a dying battery. Even a battery that doesn't have enough to start the engine will provide a bit of buffer against sudden loads. That's why it's rare to have the engine die if you get a jump start on a "dead" battery.

I'm curious about how the KL would react to no battery, but certainly not curious enough to try it!
 
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And who knows what would happen with the Auto Start/Stop systems if there was no battery!
 
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It would be disabled, since the battery voltage sensor would read zero. Assuming everything else is functioning the way it should without a battery…
Wonder if the message would read 'Stop/Start Disabled, Battery Missing' :ROFLMAO:
 

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It would be disabled, since the battery voltage sensor would read zero. Assuming everything else is functioning the way it should without a battery…
Make a video showing a cherokee running without a battery. It won't work
 

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Everything would not be functioning as it would normally. PCM would freak out as many parameters in it are tied to battery voltage. Have you read and looked into the PCM and BCM? Curious to know why you are so sure it would work
 

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Everything would not be functioning as it would normally. PCM would freak out as many parameters in it are tied to battery voltage. Have you read and looked into the PCM and BCM? Curious to know why you are so sure it would work
Curious to know why you’re so convinced I’m claiming the vehicle would run well, or at all? I said (paraphrasing for clarity) that if it ran, and if everything else functioned, the stop/start would be disabled. That’s obviously a big”if”, considering how our vehicles don’t like anything other than nominal battery voltage. I never actually claimed it would run.
 

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If you are so convinced try it? These vehicles are incredibly sensitive to voltages even with batteries installed, so all the indication is that it won't run without a battery, i would like someone to try it though
 

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What are you talking about? What about any of my comments here leads you to believe that I think it would work? I haven’t stated at all, anywhere, that I thought it would work. I said “IF” it worked as a hypothetical response to someone’s hypothetical question as to what the auto start/stop would do without a battery. Frankly, I don’t care if it would work. I’m not willing to risk bricking my vehicle and having to get towed to the dealer for a proxy alignment just to find out. So let me be clear one last time: I NEVER SAID I THOUGHT IT WOULD WORK.
 
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